The use of light-based diagnostics is growing due to their non-intrusive behavior, and potentially rapid implementation with existing techniques. One such diagnostic technique, diffuse reflectance spectroscopy, is sensitive to the absorption and scattering properties of biological molecules in tissue and thus can be used as a tool for quantitative tissue biology in vivo. One major absorber of light in tissue in the visible range is hemoglobin, which shows distinctive, wavelength-dependent absorbance characteristics depending on its concentration and oxygenation. Light scattering in tissue is sensitive to the size, density, and refractive indices of cellular structures such as nuclei and mitochondria. Thus, diffuse reflectance spectroscopy (absorption and scattering) of tissues can quantify changes in oxygenation, blood volume and alterations in cellular density and morphology. Implementation of such detection strategies, however, is limited by the bulky and expensive nature of existing light sources and detectors.